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From:   Pedro Sousa <PedroM.Sousa@synopsys.com>
To:     Asutosh Das <asutoshd@codeaurora.org>,
        "cang@codeaurora.org" <cang@codeaurora.org>,
        "rnayak@codeaurora.org" <rnayak@codeaurora.org>,
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Subject: RE: [PATCH v3 2/2] scsi: ufs-qcom: enter and exit hibern8 during
 clock scaling
Thread-Topic: [PATCH v3 2/2] scsi: ufs-qcom: enter and exit hibern8 during
 clock scaling
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Date:   Mon, 11 Nov 2019 15:54:57 +0000
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Hi Asutosh,

Please check comments.

-----Original Message-----
From: Asutosh Das <asutoshd@codeaurora.org>=20
Sent: Wednesday, October 23, 2019 5:49 PM
To: cang@codeaurora.org; rnayak@codeaurora.org; vinholikatti@gmail.com; jej=
b@linux.vnet.ibm.com; martin.petersen@oracle.com
Cc: linux-scsi@vger.kernel.org; kernel-team@android.com; saravanak@google.c=
om; salyzyn@google.com; Asutosh Das <asutoshd@codeaurora.org>; Andy Gross <=
agross@kernel.org>; Alim Akhtar <alim.akhtar@samsung.com>; Avri Altman <avr=
i.altman@wdc.com>; Pedro Sousa <pedrom.sousa@synopsys.com>; James E.J. Bott=
omley <jejb@linux.ibm.com>; open list:ARM/QUALCOMM SUPPORT <linux-arm-msm@v=
ger.kernel.org>; open list <linux-kernel@vger.kernel.org>
Subject: [PATCH v3 2/2] scsi: ufs-qcom: enter and exit hibern8 during clock=
 scaling

Qualcomm controller needs to be in hibern8 before scaling clocks.
This change puts the controller in hibern8 state before scaling
and brings it out after scaling of clocks.

Signed-off-by: Asutosh Das <asutoshd@codeaurora.org>
---
 drivers/scsi/ufs/ufs-qcom.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
index a5b7148..55b1de5 100644
--- a/drivers/scsi/ufs/ufs-qcom.c
+++ b/drivers/scsi/ufs/ufs-qcom.c
@@ -1305,18 +1305,27 @@ static int ufs_qcom_clk_scale_notify(struct ufs_hba=
 *hba,
 	int err =3D 0;
=20
 	if (status =3D=3D PRE_CHANGE) {
+		err =3D ufshcd_uic_hibern8_enter(hba);
+		if (err)
+			return err;
 		if (scale_up)
 			err =3D ufs_qcom_clk_scale_up_pre_change(hba);
 		else
 			err =3D ufs_qcom_clk_scale_down_pre_change(hba);
+		if (err)
+			ufshcd_uic_hibern8_exit(hba);
+
 	} else {
 		if (scale_up)
 			err =3D ufs_qcom_clk_scale_up_post_change(hba);
 		else
 			err =3D ufs_qcom_clk_scale_down_post_change(hba);
=20
-		if (err || !dev_req_params)
+
+		if (err || !dev_req_params) {
+			ufshcd_uic_hibern8_exit(hba);
 			goto out;
+		}
=20
 		ufs_qcom_cfg_timers(hba,
 				    dev_req_params->gear_rx,
@@ -1324,6 +1333,7 @@ static int ufs_qcom_clk_scale_notify(struct ufs_hba *=
hba,
 				    dev_req_params->hs_rate,
 				    false);
 		ufs_qcom_update_bus_bw_vote(host);
+		ufshcd_uic_hibern8_exit(hba);

Here you are creating the possibility of returning a success even if hibern=
8 exit fails.
If hibern8 exit fails the ufs recovery will be triggered and "err" variable=
 will not get updated=20
in this function, how is this handled? Did you tested this possibility?

 	}
=20
 out:
--=20
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux =
Foundation Collaborative Project.

This is just a doubt, it might make sense in this use case, please give me =
your thoughts.

Thank you,
Pedro Sousa